Join with us as ANSTO’s Senior Principal Research Scientist, Dr Andrew Smith and his team race the sun across Antarctica in search of by-products of cosmic rays.
Weather permitting, Dr Smith will blog his experiences along the way as he and the team tackle sleep deprivation and sub-zero temperatures in the name of science.
Day 7 - The A-factor has struck!
With the job of gathering samples done, Andrew and the team commenced the journey home. The first step was a trip on Priscilla a snow vehicle that has served the scientists well on their Antarctic adventure.
In this blog, Dr Smith details how the weather conditions are hampering their progress...
We assembled at 07:30 in the ‘wallow’ this morning ready to board Priscilla for the trip to Wilkins and at 08:15 we were informed that the flight had been delayed by 24 hours due to poor weather at the aerodrome.
I wasn’t too surprised as it started snowing quite heavily at about 23:00 last night and was still doing so this morning. Conditions have improved at Casey now (11:00) and there are patches of blue sky.
The last report from Wilkins at 07:30 was -9.3 degrees C with winds of 44 km/hour and gusts of 56 km/hour so its no wonder the flight was cancelled.
At this stage we are going to try again tomorrow. This makes it tricky for Krista Simon, our chemist who has to rendezvous with the samples once they clear customs in Hobart in order to get the sample processing underway. We are unable to use the laboratory at the University of Tasmania over the weekend so this will delay sample processing and thus measurement on ANTARES.
Unfortunate, but that’s Antarctica for you!
I have changed my reservations and hope to arrive back at ANSTO on Friday.
Antarctic weather facts
- The mean temperature for February was -4.3 degrees celcius
- The highest wind speed recorded for the month was 100 km/hour
- The lowest temperature recorded was -6.3 degress celcius
Day 6 - Images from the mission and getting ready to come home
With the hard work done and the samples collected, the team can now start preparing for the return trip to Australia to conduct further research at ANSTO.
Dr Andrew Smith explains the next steps with some images above illustrating their adventure...
Once the samples make it back to Hobart the three short cores are cut to size, combined, melted, filtered and passed through an ion exchange column; this is then returned to Sydney for further processing with 10Be atoms trapped inside.
Snow pit samples from each level are combined and processed similarly, but this time we are also interested in the 7Be atoms trapped along with the 10Be atoms. But without an accurate chronology all this effort would be wasted. This is where our colleagues in the Antarctic Division play an essential role, establishing the chronology of the longer core and matching it and the other samples to the ‘master’ DSS chronology.
This Antarctic Science project (#3064) doesn’t aim to go far back in time, but rather to develop a detailed record, at monthly resolution, of 7Be and 10Be concentrations. In combination with neutron monitor data, satellite observations of the Sun and numerical Global Circulation Models (GCMs) we are trying to separate atmospheric transport effects from the production signal. We have been doing this since 2000 and we are now better able to interpret the much longer records we hope to take in future years.
After collecting the samples our work was not over: Jamie (Hamilton) and Cam (Dempsey) had two more missions that night: to dismantle a GPS transponder at Law Dome Summit and to attach a wind generator to the AWS… at 03:00 by the Hagglunds headlights with the full moon in the sky and the sun rising on the horizon. Then began the long journey back to Casey, arriving at 09:15 on Friday. All up, a good day’s work!
Days 3-5 - Capturing cosmic rays from a supernova
It's down to the serious science in Antarctica.
Dr Andrew Smith and the team set off from Casey at 14:15 on Thursday 9th of February, bound for “DSS’: 5 km South of Law Dome Summit. Speed and efficiency are of the essence with this mission. With great haste the team setoff to recover shallow ice cores and snow pit samples to help study the variability of the Earth's local star - the Sun. The challenge was to get this work done before the Sun set.
With some time now to record their work, Dr Andrew's shares their experiences from the Antarctic expedition...
We arrived at 19:25 after the usual mind-numbing ride in a Hagglunds and immediately started work.
Jamie (Hamilton and Cam (Dempsey) quickly dug a 1 m3 snow pit while Ulla (Heikkila) and I got the gear ready to take PICO cores using a hand-powered Auger.
With the pit dug, I jumped in and began to square-off one face of the pit - the quarrying face. In the meantime the others began serious PICO coring. By 01:00 Friday the snow pit sampling was finished, with 36 10x10x20 cm (i.e. 2 Litre) samples taken - one from the first 10 cm level, two from the next and so on down to 0.8m. By 02:15 the PICO coring was completed: three cores of 3m length and another of 5m length.
This completed the first stage in what will be an unusual journey for the samples, or at least for the beryllium-7 (7Be) and beryllium-10 (10Be) atoms that are trapped in the ice sheet.
These atoms are radioactive isotopes of beryllium that were produced in the atmosphere by cosmic radiation. Cosmic rays continually bombard the Earth, originating deep in the universe, probably from a distant supernova. When they collide with the oxygen and nitrogen nuclei in the Earth’s atmosphere they smash them into smaller pieces and these smaller pieces in turn cause more nuclear reactions to take place as the energy of the initial cosmic ray is lost.
Some of these nuclear reactions give rise to 7Be and 10Be that become attached to aerosols and are transported though the atmosphere to the surface of the Earth. Because polar ice sheets are annually layered we can tell when they made it to the ground. But to detect them is a complex business and requires a very specialised technique called Accelerator Mass Spectrometry, or ‘AMS’ and a very large particle accelerator called ANTARES at ANSTO in Lucas Heights, Sydney. 10Be has a very long half-life of 1.4 million years, so we have plenty of time to make the measurements. 7Be has a very short half-life of 53 days, and this is where the Air Link comes in. We are able to rapidly return the samples to Australia, process and get them in to the accelerator quickly for measurement.
Speed is of the essence! The snow pit samples are adjusted in size to compensate for the radioactive decay of the 7Be - deeper samples are older and so must be made larger.
The rate at which the 7Be and 10Be is produced depends upon the intensity of the Sun. This is because most of the cosmic rays are electrically charged particles and are thus deflected by the Sun’s magnetic field that permeates our Solar system. For instance, the well-known 11 year Solar cycle can be readily distinguished in the measured concentration of 10Be in the ice sheet. But the Sun also varies over much longer timescales and we are interested to know about this because the Sun drives the Earth’s climate system.
Day 2 – Racing the sun in the name of science
The ANSTO team experienced sub-zero temperatures in their first real day in the snow as part of an expedition in search of by-products of cosmic rays.
Senior Principal Research Scientist, Dr Andrew Smith in a pit. (Image by Dr Andrew Smith)
Dr Smith blogs the experience after returning from Law Dome, a large ice dome which rises to 1,395 m directly south of Cape Poinsett, Antarctica...
We have just returned after a successful overnight expedition; I need a shower and sleep.
I got quite a few photos, despite fairly poor conditions with temperatures dropping to a low of -13 degrees C and wind speeds around 30 km/hour.
Amazingly, we were racing the sun - it gets quite dark hear at 3 in the morning here in Antarctica, which I’m sure would be hard for some to fathom back home.
Both Ulla (Heikkila) and I are have been joined by field training officer Jamie and Dieso Cam taking PICO cores. You can see in one of the photos the size of the pits we work in when obtaining these samples.
We will hopefully get these samples back home for further analysis to detect Beryllium-7 and Beryllium-10 atoms in the ice, and hopefully get some good data on solar activity.
Postdoctoral Research Fellow, Dr Ulla Heikkila with field officer Jamie and Diesco Cam taking PICO cores.
Day 1 – Weather conditions delay start of expedition
The adventure began for the team when they arrived in Hobart on Monday 6 February and discovered via SMS that their flight to the Wilkins Aerodrome would be delayed by 24 hours.
Wilkins Aerodrome is located approximately 70 km South East of Casey and serves as the Antarctic terminal for the intercontinental air service…
Ulla and I arrived in Hobart from Sydney on Monday only to get an SMS that the flight had been delayed by 24 hours due to bad weather at Wilkins. Fortunately our kitting appointment and pre-departure briefing were still held that afternoon.
The re-scheduled flight departed at 06:00 on Wednesday 8th landing at Wilkins Aerodrome, which is a sight to behold from the air.
Due to predicted worsening weather it was decided we would leave today for Law Dome summit. In fact, just after lunch in 1 hour. It’s been a mad panic getting everything sorted.