HAMNET Report 29 October 2017

HAMNET congratulates the RAE candidates who wrote and passed their exams this week, and have been allocated their new call-signs. We look forward to welcoming you all to the bands, and repeaters, promise to do our best to guide you through all the pitfalls encountered as you start your exploration of RF electronics, and hope at least some of you will join HAMNET, the emergency communications wing of the South African Radio League. We practise providing communications to sporting events, local or national disasters, and car rallies, and have groups in all the regions in South Africa, so look on the SARL website for the HAMNET page down the left hand side of the home page, and pick up some information there on your area’s activations.

Today sees HAMNET Gauteng South assisting with the Carnival City road race for cyclists, and next Sunday the Tshwane Classic race. Good luck with these two events, Leon, ZS6LMG, and all your operators. We hope you’ll report to us on both the events.

Richard Talcott, writing in Astronomy’s local group Blog, has commented on something that I’m sure a lot of you have been puzzling over. He says:

“While discussing the possibility of intelligent life in the universe over lunch with his fellow scientists, Nobel Prize-winning physicist Enrico Fermi asked the simple question: “Where are they?” The line came to be known as the “Fermi Paradox,” and the argument boils down to this: If the universe is teeming with life, and some reasonable percentage of that life has developed advanced technology, then these civilizations should have populated our corner of the Milky Way long ago. Several potential solutions to the paradox exist, ranging from the possibility that we are alone in the cosmos to the chance that the aliens already live among us.

[Last] Thursday at the 49th annual meeting of the Division for Planetary Sciences in Provo, Utah, S. Alan Stern suggested a new solution: Perhaps the aliens populate ocean worlds cut off from the outside universe by thick crusts of ice or rock. Stern, best known as the principal investigator on the New Horizons mission that explored Pluto, points out that we now know of at least four such worlds in our solar system, and evidence suggests there could be five or more additional ones. And there’s no reason to suspect that they wouldn’t be common among the exoplanet population.

Such water worlds might even have a few advantages over their surface-water cousins. For one, they would be better protected from external hazards like harsh radiation, large impacts, and changing climates. Interior oceans would provide a more stable environment that poses less risk to any life that might develop. But their thick crusts also naturally isolate them from the universe beyond. They would be hard to detect and would face enormous difficulties communicating with the outside world — if they even knew a outside world existed.

The existence of these ocean environments hidden beneath thick shells could offer an elegant solution to the Fermi Paradox, and fittingly one that Enrico and his lunch buddies could never have imagined.”

The most recent discussion of subsurface water worlds surrounds Enceladus, one of the many moons of Saturn, recently researched by the Cassini spacecraft, which burned up in Saturn’s atmosphere after a successful 13 year mission of investigation. Using magnetometers on board Cassini, researchers proved that Enceladus has a dry crust, which has been fractured, and which is leaking water vapour from within, with other molecules of organic materials like methane, revealed by spectrometers on board! The question is, what is going on under that crust? When Cassini’s fuel cells were running dry, and it was decided that Cassini should be allowed to self-destruct in Saturn’s atmosphere, it was purposely made to crash into Saturn, and not allowed to drift to its demise, in case it hit one of the moons and polluted the atmosphere, thereby preventing future scientists from ever being absolutely sure whether the life forms there were indigenous, or accidentally imported from earth! We watch for further results of the investigations into extra-terrestrials with great interest.

Terrestrials, on the other hand, are starting to lose themselves or come to grief on Table Mountain again, as the weather starts to warm up here in the Cape. There were at least seven searches and rescues on the mountains in the last eight days, one of them a fatality as a walker fell to her death. The HAMNET volunteers, working as they do with Wilderness Search and Rescue, which is also a completely volunteer organisation, of climbers, off-road rescue and 4X4 drivers, are gearing up for the many calls which will come in. WSAR cannot stress strongly enough how treacherous Table Mountain can be, and how important it is for hikers never to hike alone, always to take warm clothing along, to tell others where they going and how long they expect to be, and to take fully charged cell-phones and even reserve power banks, as well as food and enough water, in case they are trapped on the mountain overnight. A sunny warm day down at sea level is not necessarily a warm windless day on top of the mountain! Please be warned, if you are contemplating going up the mountain, and take this advice seriously.

Tropical Storm Selma, a small storm off-shore just South West of El Salvador in the Pacific, is threatening the coastal towns there, with an orange alert for high humidity, heavy rains, flooding of rivers and general floods in Southern and central regions of Gautemala yesterday, and possibly today (Sunday). Their VHF repeaters are all linked, so hopefully, internal messages will be transmitted on VHF, but Guatemala’s Amateur Radio Club uses 7075kHz and the Central American Chain 7090kHz LSB, so please be aware of 40 metre traffic, and listen carefully for skip before you use these frequencies this weekend.

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.