Monday, 30 August 2010

Night Four of our Jupiter observations, Mauna Kea Observatory

This is our last night observing, so we had a last look at a Mauna Kea sunset, coming up just after dinner at Hale Pohaku. We also brought my wife, Vanessa, my daughter, Lisa, and her partner, Mark, up to see the telescope. It was Lisa and Mark's first time on the mountain. Mark is a professional artist (, specialising in abstract painting. He was absolutely stunned by everything he saw - the light, the colours of the mountain and of the sky, the silhouettes of the mountains and the telescopes as the sun went down - and now has enough photos to inspire his art for years ahead.

On the way up to the summit we stopped by the roadside to look at the Hawaiian Silversword. This is an endangered species in Hawaii, and - according to the Institute of Astronomy's website on Mauna Kea Plants ( is a member of the "Silversword Alliance". Sounds very dramatic!

During the last Ice Age, Mauna Kea was covered by glaciers. It must have been absolutely spectacular, since the volcano was active then, spewing out red hot lava by the millions of tonnes. On the ride up to the summit, you go through the middle of the Ice Age Reserve. You can really see the effects - large, smooth valleys carved by the ice, and huge mounds of boulders, called moraines, that were carried by the glaciers and then left there when the ice started to melt again.

Back on the observing front, sometimes things don't quite work right, and you just don't seem to be able to fix it. Tonight is one of those nights. The sky is beautifully clear, the spectrometer is working perfectly, but we have had some trouble with the guide camera, which has decided to save our images rather differently from normal. Nothing we cannot live with, but unexplainably odd. And it means we are having to do manually what used to happen automatically - keeps us focussed.

As soon as we finish tonight, with another haul of amazing images and spectra, we will be heading back to Hale Pohaku for breakfast and then down the mountain to Hilo. It's always sad to leave the Observatory behind, but the extra oxygen at sea level is very welcome. Indeed, it can often inspire you to take on tasks you would normally try to put off. This time I have promised Henrik he won't have to cut down any trees in the jungle that backs onto my wife's back yard!

Our thanks go to all those at the Observatory and at Hale Pohaku who have help to make our observing run such a success.

Sunday, 29 August 2010

Night Three of our Jupiter observations, Mauna Kea Observatory

Our second night's images are now available as a rough movie on YouTube, thanks to Tom Stallard, who is working back in Leicester on our data: if you search on "Jupiter through an Earthly veil" or "Jupiter IRTF", you will find it easily. The movie shows many of the familiar features of the planet, even though it is a set of infrared images, not pictures taken in normal, visible, light. Here's the movie:

The banded structure of Jupiter is clear, with the various belts and zones. About half-way through, the Great Red Spot (showing white in our movie) rises over the edge of the planet, and travels towards the noon meridian. Before that happens you can see the closest of Jupiter's big moons, Io, moving into eclipse on the western side of the planet (on the right of our movie); it comes out of eclipse towards the end of our image set.

Io is the most volcanic body in the Solar System, with plumes of sulphur that can sometimes be seen reaching far out into space. So it glows very brightly in our movie - it's the brightest thing we see.

The aurorae can also be seen clearly around the poles. In the north, the aurora starts as an oval that then turns into a bright line as it moves onto the edge of Jupiter. In the south, the southern aurora is only seen as a bright line at the pole.

In previous blogs I have mentioned that we sleep at the 3,000-metre level, at Hale Pohaku, whilst the telescopes are at 4,200 metres. That means a 12-kilometre drive up each night to observe and then back down again in the morning. And that means a drive of 6 kilometres at the start over a dirt road before you reach the paved road at the summit.

The dirt road has the tendency to develop the texture of an old-fashioned wash-board, with deep ridges. This can be dangerous, particularly on the way down, as vehicles only have grip when the tyre is in contact with the top of the ridge. People who have not taken this into account have had problems; tragically, sometimes the results have been fatal. So the drive to and from the telescopes is not without its challenges.

Tonight is another gloriously clear sky. We left Hale Pohaku with Scorpio setting and Taurus rising, two beautiful constellations. With Taurus come the Pleiades, that lovely cluster of small stars. At the summit, you can often see Nine, instead of the usual, Seven Sisters. The Pleiades are testimony to the global nature of astronomy - in Hawaii, they are the Makali'i, the Japanese have named their telescope - Subaru - for them. Wikipedia gives a total of 20 names for this group of stars. They have clearly inspired cultures around the world.

It's the turn of the southern aurora to strut its stuff tonight, after the northern lights last night. The reason we see the aurorae differently each night is because - like Earth - Jupiter's magnetic pole is offset from its rotational pole. Since they are centred on the magnetic poles, that makes the aurorae appear to wobble back and forth as the planet rotates.

One of our key objectives is to see if we can observe waves travelling down from the aurorae towards the jovian equator. This would be a sign that energy from the polar regions, where we have the strong winds and electric currents, can make it down to lower latitudes. That, in turn, would help us to understand a problem that has plagued planetary scientists since the arrival of the Voyager spacecraft in 1979 - why is Jupiter, and the other giant planets, Saturn, Uranus and Neptune, so hot?

For Voyager measured the temperature of the upper atmosphere around the equator of Jupiter to be around 900 degrees, several hundred degrees hotter than can be explained by the input of sunlight alone. In a previous blog, I mentioned that the energy generated by the winds and currents associated with the auroral/polar regions was 100 times that due to the absorption of sunlight. So an obvious solution would be to transfer some of that energy down from the poles to the equator.

But not so fast: Jupiter is spinning nearly two-and-a-half times faster on its rotational axis than is the Earth - a Jupiter day is just 9 hours 55 minutes. Jupiter's diameter is more than ten times that of Earth. The result is that very large forces, known as Coriolis forces, are generated. And that means that any energy-bearing wind that starts out going from the pole towards the equator tends to get turned westwards, and never reaches its original destination.

So planetary scientists still cannot account for Jupiter's high upper atmosphere temperatures. Our goal from these observations is to see if we cannot add a little bit more to our understanding of that puzzle - hence the search for waves.

When we are working at the summit, it is nice to have a bit of comfort food to keep us going. For Henrik, that means several cans of fizzy drink (sodas, US English) per night; for me, it's peanut butter sandwiches and cocoa - the perfect diet.

Afternoon Three of our Jupiter observations, Mauna Kea Observatory

I'm now sitting in the IRTF office at Hale Pohaku (HP), the 3,000-metre level dormitory complex where we sleep after observing. There is more oxygen down here, so it makes for (somewhat) clearer thinking. Last night's images have already been put into movie form, fairly crudely, so there is a lot of image processing to do.

The spectra take longer to analyse. But spectroscopy, which tells you about temperatures and densities of the molecules you are looking at, contains the real physics. I'm one of these people who don't believe the pretty pictures until I can see the spectra.

Being actually present at the telescope when you are observing gives you so much more insight into what a complex operation modern astronomy is. If you pick up a scientific paper in Astrophysical Journal, Monthly Notices, Nature or Science, you never get the real picture of just how much goes into getting the data upon which all science is supposed to be based. Too many theoreticians think it drops like manna from heaven.

Because I'm currently working on the NASA IRTF, I'll use that as an example. Starting at the "top" - in terms of altitude, not necessarily seniority - you have the telescope operators. They are the guys who actually run the telescope: if you thought NASA would allow some ham-fisted amateur like me to play with their telescope and maybe run it into the dome or commit some other mortal sin with it, you have to be joking.

Seated alongside us for this run, we have Dave Griep and Bill Golisch. They are some of the most experienced TOs on the mountain. They have literally worked on Mauna Kea for decades, from the days in the late '70s and early '80s when the Mauna Kea Observatory was establishing itself as the world's premier site for astronomy, particularly in the infrared wavelengths. Dave has enabled us to observe when the winds were literally shaking the dome; Bill's inventiveness for work-arounds when what we want to do is not quite standard is legendary. I have also worked many times with the the two TOs, Paul Sears and Eric Volquardsen, both top-rate TOs whose love of the telescope makes for effective and efficient observing.

Coming up to help out, too, are the various support astronomers. Last night we were lucky that Bobby Bus from the Hilo branch for the Institute for Astronomy was at the telescope when we arrived just before midnight. He stayed on for a couple of hours beyond his shift to help us with guiding the telescope on Jupiter, and came up with a novel technique of using Jupiter - which spans an impressive 49 seconds of arc across the sky at the moment - as if it were a mere pinpoint of light. Even he was impressed by how well it worked.

While the astronomers and TOs are sleeping through the day, the telescope is in the hands of the day crew. They fix and upgrade and generally ensure that these multi-million dollar science factories perform to ever more demanding standards. At IRTF the Observatory Superintendent George Keonig leads a team who work at 4,200 metres in (almost) all weathers to see to it that astronomers get their data. George is backed up by his foreman Lars Bergknut, whose favourite phrase seems to be "are you sure you want to that?" before he gets the engineering and software team to work out a way to enable awkward astronomers to do things with the telescope that would make you blush. "Can do" gets things done!

Telescopes are no good unless they have instruments. In the rush to build ever-bigger light buckets, this is often forgotten. One of the saddest outcomes of the UK's Science and Technology Facilities Council's drive to save money is that its flagship infrared telescope, the United Kingdom Infrared Telescope (UKIRT) - itself one of the original 1970s "big three" on Mauna Kea - is now restricted to imaging survey work. A unique set of instruments, including one that enables astronomers to take spectra in polarised light, are now gathering dust. Britain should be ashamed, very ashamed.

IRTF has its teams of instrument builders. John Rayner, an ex-pat Brit who fell in love with Honolulu (and who wouldn't?) a quarter of a century ago, is currently putting together a new spectrometer for the telescope that will more than double the spectral resolution - the ability of the telescope to discriminate between individual wavelengths - of IRTF, and keep it competitive even in the age of telescopes up to ten times larger than its 3-metre mirror.

This high-resolution spectroscopy is important because, as well as measuring gas temperatures and densities, we can work out how fast the gas is going. On Jupiter, we regularly measure winds in the polar regions, where the aurorae are formed, of between 1 and 2 kilometres per second. These generate huge amounts of energy: the winds themselves and electric currents that go with them heat Jupiter's upper atmosphere more than 100 times more effectively than sunlight alone. John's new instrument should be available for IRTF to work alongside a space mission to Jupiter called JUNO, which, unfortunately, does not have a high-resolution infrared spectrometer on board (despite my arguing for one).

No run-down of IRTF is complete (and this one leaves out many, many of the telescope's key players) without a mention of its current director Alan Tokunaga. Based in Honolulu, but regularly visiting his beloved telescope, Alan himself knows all the dififculties of building top-quality instruments. His CSHELL spectrometer, now nearly 20 years old, still delivers great science, a testimony to his design skills and ability to see complex projects through. It costs about $10,000 a night to run IRTF, and it's Alan's job to ensure that NASA supports the IRTF financially so that it can support NASA's much-more-costly space missions.

And on a personal note, I cannot leave this blog entry without a mention of Alan's predecessor as IRTF director. Bob Joseph took over as director in 1989. I had met him for the first time earlier that year, where I talked about the discovery (as it then was) of the H3+ molecular ion on Jupiter. Bob was a "merging galaxy" person, looking at what happens when galaxies crash into one another, releasing huge amounts of energy and triggering massive star formation events. But IRTF was (and still is) 50% dedicated to planetary science.

So Bob asked me if I wanted to work with him on a project to exploit this new discovery of H3+. Of course, I agreed. His idea was that he would make the observations using his "director's time" in Hawaii while I did the calculations back at University College London. Fat chance!

The opportunity to come to Hawaii was not to be missed, the privilege to work at Mauna Kea Observatory an irresistible temptation. Bob taught me infrared astronomical observing in March 1990, and introduced me to Ken's House of Pancakes in Hilo. The rest, as they say, is history.

Saturday, 28 August 2010

Night Two of our Jupiter observations, Mauna Kea Observatory

We are coming up to the half-way stage of our four-night run here at the IRTF. The second night has been productive, if a little more challenging than the first.

Firstly, the weather started off a little less friendly. Even though Mauna Kea's summit is 4,200 metres above sea level, and above most of the heavier cloud decks, we can still be affected by high-altitude cirrus clouds. Tonight we had the wispy variety, not enough to stop us observing but enough give us some trouble at the start of our shift.

Then we had to use a different system to guide the telescope on our target Jupiter. Again, nothing to stop us observing, but it meant learning a new routine on the fly. And at altitude, your brain does not function quite as crisply as normal. But we had help in the shape of Bobby Bus, one of the full-time staff astronomers at the Institute for Astronomy in Hilo.

One of the reasons I like to be at the telescope when I am observing, rather than working remotely over the internet, is that you can get help much easier from people on the spot. The other is that you meet up with people and some chance collaborations emerge.

This trip, we have Amanda Gulbis, from the South African Large Telescope, working on the IRTF for the six-hour shift up till midnight. She is testing out a new camera that works alongside SpeX. So tonight, Amanda stayed beyond her normal midnight down-time, taking her own images of Jupiter, testing the camera and providing us with a view in visible wavelengths to complement our infrared pictures. So a genuine "two for the price of one" situation, profiting us both.

During the course of yesterday, Tom Stallard, who is at the University of Leicester along with Henrik and our long-time collaborator, put together a neat programme to turn our images of Night One into a movie. There is still quite a bit of image processing to do, but the raw movie looks impressive, as the jovian aurorae come in and out of view as the planet rotates.

Sleeping during the day has been a problem for both Henrik and myself, so we will be pretty tired by the time our shift ends in an hour or so. But tonight's work seems to be every bit as good as last night's and that makes up for the lack of sleep.

Friday, 27 August 2010

Night One of our Jupiter observations, Mauna Kea Observatory

It's 4am Hawaii Standard Time, and we are 2/3 of the way through our six-hour shift. And what a great shift it has been. The sky is perfectly clear, there is almost no wind and the "seeing conditions" - the blurring of our images due to the Earth's atmosphere (a useful thing for breathing, but it gets in the way for astronomy) - is very slight.

We are simultaneously measuring Jupiter's spectrum along its noon meridian and taking images of the whole planet, using an instrument on NASA's Infrared Telescope Facility called SpeX. That means we can properly locate the spectra we are taking on the disk of the planet. We take the images at a shorter exposure than the spectra. So, by the end of the night, we will have taken a total of 250 images and 150 spectra. That's a PhD's worth of data in one night, and we have three more to go.

As I'm writing this, the Northern Aurora of Jupiter is coming into full view on the disk of the planet. The Southern Aurora has pretty much set, and all that we can see looks like the smile on the Cheshire Cat. These aurorae are the most powerful in the Solar System - 100 times brighter than anything we see on Earth. They are testimony to the dynamic coupling between the planet's atmosphere and its enormous magnetosphere, the region of space controlled by Jupiter's magnetic field.

To give some idea of the scale: Earth's magnetosphere stretches about 60,000 km in the direction of the Sun, and about 600,000 km in the direction away from the Sun, its tail dragged out by the stream of particles thrown out by the Sun called the Solar Wind. Jupiter's magnetosphere extends 2 million km in the sunward direction, and some 750 million km downstream. In fact, it reaches all the way to the orbit of Saturn.

Lit up, if it could be, Jupiter's magnetosphere would appear in the sky to be more twice as large as the Moon. It is this giant structure that heats the top of Jupiter's atmosphere, by throwing energetic particles at it and generating enormous currents and electric winds. We are probing this by looking at the spectrum of the H3+ molecular ion I talked about in my last blog.

We have analysed one of the spectra which us a temperature in region of 950 K. This is much higher than sunlight alone can produce. It clearly shows how much Jupiter's magnetosphere is responsible for the conditions that occur in the upper atmosphere.

But it is not all one way traffic. As Jupiter rotates (once every 9 hours 55 minutes), so does its magnetic field. And that field drags the charged gas that fills the magnetosphere, known as plasma, along with it. Indeed, this mutual interaction spins up the magnetosphere, heats up the atmosphere and - since there s not such thing as a free lunch - actually slows down the planet as it spins on its axis. No need to worry, though. At the present rate, Jupiter will carry on spinning for at least ten times the lifetime of the Solar System.

Thursday, 26 August 2010

Observing Jupiter from Mauna Kea Observatory, Hawaii

Mount Hualalai viewed from the
MKO dormitories. Credit: Steve Miller.
I have been visiting Hawaii to use the telescopes of the Mauna Kea Observatory for 20 years. But I still get a thrill every time I come up here. The Big Island of Hawaii is like nowhere else on Earth.

The Hawaiian chain is made up of some of the most isolated places in the world, set in the middle of the Pacific Ocean. Once you get to the West Coast of the United States - and that involves an 11-hour flight from London where I live most of the time - it is still another 5 to 6 hours of flying over the ocean. Hilo, on the eastern shore of Hawaii, is at longitude 155 West and latitude 20 North, with an 11-hour time lag to London in the summer.

Mauna Kea viewed from across
Hilo Bay. Credit: Steve Miller.
Hilo is my favourite place in Hawaii: it is where my wife grew up and still has her family home; a place to take a few days rest after the long flight over and before heading up the mountain.

The prevailing westward-blowing Trade Winds (usually) bring rain to the eastern side of Hawaii. (This year, there has only been 50cm of rain so far, very dry by Hilo standards.) That makes for tropical rain forest. But the 50 kilometre drive up to the observatory dormitories takes you up 3,000 metres in altitude, and the vegetation changes from lush "jungle", through Ohia forest, to scrub, to not very much at all except a few bushes and plants that the Brits have christened "triffids" for their odd, slightly menacing look.

A pukiawe bush on the slopes of Mauna
Kea, an example of the mountain's
unique plant life. Credit: Steve Miller
Looking westwards from the dormitories over the lava fields and cinder cones down towards the Kona side of the island, you are looking out over what becomes desert. The two giant mountains - Mauna Kea and Mauna Loa - that dominate the centre of the Big Island ensure that almost all of the rainfall happens on the eastern side of the island: Kona is pretty much in a total rain shadow.

Henrik and Steve outside the
NASA IRTF. Credit: Steve Miller

Tonight is our acclimatisation night. Although we will go up to the summit to watch the sunset, and get a bit of 4,200-metre altitude exposure, Henrik Melin (my co-observer) and I will spend most of the night at the 3,000-metre level where the dormitories are. We will use the time preparing, logged on to the interface of the NASA Infrared Telescope Facility (IRTF), setting up for our four six-hour shifts observing Jupiter.

The mountain top of Haleakala on the
neighbouring island of Maui viewed
above the cloud tops. Credit: S Miller.
Our goal is to map the emission from a molecule (strictly speaking a molecular ion) called H3+, the third form of Hydrogen, after the H atom and the H2 molecule. This ion is formed high up in Jupiter's atmosphere, where the pressure is less than one millionth of a bar, and temperatures soar to well over 1,000 K. It traces high levels of energy inputs: around the poles of Jupiter, it shows where high energy particles smash into the top of the atmosphere causing bright aurorae, like our Northern and Southern Lights on Earth; at lower latitudes, it is formed ultraviolet radiation from the Sun.

There's a free drink on Steve at the Rome
EPSC for the first person to email him
 with the correct identification of this!
We will use spectroscopy, breaking up the (infrared) light from Jupiter into individual fingerprint lines from H3+, clearly identifying the molecule as if we were forensic scientists. But better - spectroscopy not only tells us who left the tell-tale fingerprints, but we can also say how hot their "hand" was at the time.

The domes of the twin Keck 10-metre
telescopes viewed against the
setting Sun. Credit: Steve Miller

IRTF is definitely not the biggest telescope in the suite available on Mauna Kea: with a mirror that comes in at just under 3 metres in diameter, it is dwarfed by the twin 10-metre Keck telescopes, and Gemini and Subaru, both at 8 metres in diameter. But it is one of the older generation. It opened in 1979 alongside the United Kingdom's Infrared Telescope (UKIRT) and the Canada-France-Hawaii Telescope (CHFT).

And in many ways it is my favourite. It was the first telescope I used here in 1990. It devotes 50% of its time to solar system science. And it still welcomes observers at the summit to do time-critical hands-on observations.

Sunday, 22 August 2010

Europlanet's been blogging from Mars (or as close as you can get on Earth)!

Europlanet has a Transnational Access activity that allows scientists to access state-of-the-art planetary research facilities in other European countries.  As part of this programme, Europlanet funds field trips to planetary analogue sites - places on Earth that resemble landscapes found elsewhere in the Solar System.

We have set up dedicated blogs for some of these trips:

In May, Felipe Gómez Gómez and crew visited Chott El Jerid, a dry salt lake in Tunisia, which closely resembles areas near the Martian poles.  You can read his blog at:

Liane Benning and colleagues on a
sampling trip. Credit: D Tobler
In August, Liane Benning and Dominique Tobler went to the island Svalbard to look at how life has evolved in the snow and ice of arctic tundra and glaciers and to help them understand how life could exist on other planets in our Solar System.  You can read Liane's blog at:

Saturday, 21 August 2010

Welcome to the Europlanet Blog

Europlanet field trip to Chott el Jerid,
Tunisia, a Mars-like place on Earth.
Credit: Felipe Gomez
The Europlanet Blog gives an insight into the work and lives of Europe's planetary scientists. Members of the Europlanet community will be blogging here about their activities, including observational campaigns using ground-based telescopes, involvement in space missions, field campaigns to sites on Earth that resemble places elsewhere in the Solar System, as well as meetings and conferences.

The exploration of our Solar System is one of the most exciting and fastest growing areas of scientific research. Through postings on this blog, we hope to share that adventure.